The present invention is directed to a device for handling radioactive material used in connection with the irradiation of malignant tumors (radiation therapy).
Radiation therapy is a common and accepted procedure for treatment of malignant tumors. A particular variant of radiation therapy, brachytherapy, is used for both interstitial and intercavitary applications. In brachyrnerapy, thin, hollow conduits (catheter tubes and/or steel needles) are initially placed at precise locations within or adjacent to the tumor, such that the ends of the conduits are accessible outside the patient's body. Thereafter, small, precisely measured quantities of radioactive material (most commonly radioactive isotopes of iridium, iodine or cesium) are placed within the conduits (commonly termed, "afterloading") and maintained in place for a selected period of time. When the therapy session is completed, the radioactive material is withdrawn from the conduits and placed in waste storage for future disposal. The number of radioactivity-loaded conduits varies with each case depending on various factors such as the size of the tumor and its location, but it is frequently as many as 10 or 30 and is sometimes greater than 50.
The small quantities of radioactive material are generally afterloaded into the pre-placed conduits by placing the radioactive material within the forward end of flexible tubes and then pushing the tubes into the conduits. The flexible tubes are commonly made of low friction material such as a plastic. The radioactive material is commonly placed at the forward end of the tube in several, discrete quantities, called "seeds." The seed-containing flexible tubes are commonly termed "ribbons."
Afterloading ribbons into a patient and removing the ribbons from the patient are procedures which require caution so as not to expose therapy personnel to repeated dosages of radiation. Historically, therapy personnel have afterloaded and removed the ribbons manually, using long, forceps-like tools and working around lead shields to minimize their radiation exposure. By this manual procedure, ribbons are removed from their radiation-insulated storage containers and placed, one at a time, into the interstitial or intercavitary conduits. Later, after the therapy session is complete, therapy personnel reverse the procedure, removing the ribbons from the conduits one at a time and placing them in a radiation-insulated storage container for future disposal. The procedures are obviously awkward, time consuming and, to an extent, dangerous to therapy personnel.
Devices for automatically handling the ribbons by mechanical, non-manual means are known in the art. However, these devices are limited in their utility by the fact that they cannot be disconnected from the ribbons during the therapy sessions. Consequently, the patient remains "attached" to the device, an obvious inconvenience to the patient. Furthermore, the device is "tied up" with the therapy of a single patient, an equally obvious economic problem of significant proportions to the medical institution providing the therapy. Consequently, the practical applicability of the automatic ribbon-handling devices of the prior art have been restricted almost exclusively to snort (usually, high-dosage) therapy sessions of less than an hour or so. Longer therapy sessions continue to require the time-consuming and dangerous manual handling of the ribbons during afterloading and subsequent removal.
In view of these problems associated with the existing ribbon-handling techniques and devices, there is a need for a device which can afterload radiation-containing ribbons into a radiation therapy patient, which can remove such ribbons from the patient, and which can dispose of such ribbons, all without exposing therapy personnel to radiation hazards, and which can be detached from the ribbons during the therapy sessions so as to free up both the device and the patient.